p-Toluenesulfonic acid monohydrate → 6-Benzyl-3-(4-chlorophenyl)-2-(2,4-dichlorophenyl)-2,6-dihydropyrazolo[3,4-c]pyridin-7-one

Participants

Reaction Steps

A mixture of 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-1H-pyrazole-3-carboxylic acid (2,2-diethoxyethyl)-amide (I-1A-1a; 528 mg, 0.92 mmol) and p-toluenesulfonic acid monohydrate (175 mg, 0.92 mmol) in toluene (5 ml) was heated to reflux in round bottom flask fitted with a Dean-Stark condenser. After 1 hour, the reaction mixture was cooled to room temperature, and then extracted from saturated aqueous sodium bicarbonate with ethyl acetate. The combined organic layers were washed with brine, dried (MgSO4), and concentrated in vacuo. The crude material (0.49 g) was purified on a Biotage™ Flash 40S column using 10-20-40% ethyl acetate in hexanes as eluant to afford I-1A-1b as a solid (69 mg, 16%): +ESI MS (M+1) 480.1; 1H NMR (500 MHz, CD2Cl2) δ 7.50 (d, J=1.5 Hz, 1H), 7.48 (d, J=8.3 Hz, 1H), 7.42 (dd, J=8.3, 2.1 Hz, 1H), 7.38-7.27 (m, 7H), 7.18 (d, J=8.7 Hz, 2H), 6.95 (d, J=7.5 Hz, 1H), 6.42 (d, J=7.5 Hz, 1H), 5.21 (s, 2H).

Provenance & Evidence